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Another correction to the Bentley service manual (PTFE Crankshaft Seals)
Good morning everyone! I thought I would share another experience in hopes you can avoid the frustration I experienced attempting to install an new front crankshaft seal. My first attempt (without the special tool) at changing this seal was part of a timing chain replacement; the seal came with the timing chain kit I purchased from ECS tuning. The Bentley service manual tells you to apply oil to the tool and to the crankshaft hub prior to installing the seal. According to many website posts, applying oil to a PTFE seal will cause it to fail immediately, so don't. See this link: https://glaser.es/en/service-downloa...tallation.aspx
After doing some more research on these PTFE seals, I used spray brake cleaner on the tool and applied some to a shop towel and cleaned the contact surface on the crankshaft hub. The installation went perfectly, and then I let the seal rest for the recommended 4 hours. Finally, I managed a leak free joint.
Another word of caution; the step-by-step instructions at Pelican Parts.com (fig 10) also says to apply oil prior to installing the seal. Don't. Here's another link from the seal manufacturer:
At :50 in the video, you can see the lovely mechanic clean the shaft surface before installing the seal. At 1:14 in the video, you can see the instructions from the seal manufacturer have an illustration of an oil can with a red circle with a line through it. At the 1:16 mark, you can see the illustration with the 4 hr timer before you start the engine. My first seal came with these instructions too, but I decided to go with what Bentley was telling me ... oops!
I followed the manufacturers instructions and it went well. I have also seen Youtube vieos of people applying oil to the outer casing/seal housing at the same time - that is just asking for a seal to blow out, the last thing you need! Agree that every surface has to be degreased fully including the outer contact with the seal. NO OIL anywhere near a crankshaft seal, either end.
The tool is nice to have but I found that the old seal was perfect for gently pushing home the new one and gets it to the correct depth too. Again, clean off any oil first.
I've been wondering the same thing and it's good to get some confirmation here. I noticed even the factory mini manual states to lightly coat the installation tool ( not the crank hub or outer casing ) and have been assuming this is where the Bentley instructions, along with most other tutorials I've seen, like pelican, are coming from. Think it's possible that a small amount of oil on *only* the installation tool may not be enough to interfere with the PTFE sealing process?
Also which brand of seal did you use? Another thing I noticed is that not all installation sleeves are created equal when it comes to using the special tool. I tried a Corteco seal first, and that installation sleeve was a joke, it neither fit over the installation tool or the crank hub, rendering it useless at my skill level.
I ended up installing the seal without oiling the tool, hub, or seal. It worked perfectly, and I'm entirely leak-free. Disclaimer, I had a brand-new crank hub and clean install tool. The other thread has some interesting points about the oil potentially taking some risk out of some minor imperfections on a used hub.
Dry was the manufacturer's recommendation, and it worked for me too.
I was doing a timing chain replacement because of a small break in the plastic guides. I wasn't happy with some pitting on my original hub. I'm OCD with this stuff, I'd rather replace it when I have it off.
BTW that engine block plug right above the hub has been known to leak when guys plug up their PCV port. It makes it appear that the crankshaft seal is the source but its actually the plug because it dribbles down onto the crankshaft seal.
10-28-2018, 08:40 AM
